The invention relates to machines for packaging doses of medicinal product in hard gelatine capsules.
More particularly, the invention relates to an apparatus for measuring and dispensing predetermined amounts of powdered material used in composite machines of the type which operate intermittently and are provided with at least one vertical axis carrousel, to which there are attached the bodies of tube-type volumetric distributors which are also vertical, with the open end of the tube oriented downwards, at which end a movable plunger is thrust upwards by elastic means, and is provided radially with a projection which extends from the said body through a longitudinal slot, and which is normally supported against stops which are supported by a plate fitted onto the said carrousel, and connected to the latter by axial adjustment means. By adjusting these adjustment means, the said plate with the stops can be lowered or raised in order to raise or lower the plunger of the distributors, and thus respectively increase or decrease the useful volume of the tube of the distributors.
In the machines in question, the tube-type distributors are mounted on the carrousel in two opposite groups, and the carrousel is alternately rotated by 180.degree. and raised and lowered in order to insert the tube of a group of distributors in a store beneath, which contains a correct layer of the product in powder and/or granule form to be distributed, such that the free chamber of the tube is filled uniformly with product. By means of the carrousel which supports them, the distributors are plunged into the store of product, then raised, rotated by 180.degree. and aligned with the bases of capsules which are supported by the carrousel for handling the hard gelatine capsules. At this point the distributors with the dose of product are lowered and abutted with the base of the capsules into which they unload the dose of product when respective thrust devices act on the movement pieces of the distributors. When the dose of product has been unloaded, the thrust devices rise in order to enable the plunger of the distributors to return resiliently into the high, cycle start position, after which the distributors are also raised and returned to cooperate with the store of product, for repetition of a new work cycle.
According to the present state of the art, in order to vary the dose of product formed by the distributors, it is necessary to adjust the machine when it is at a standstill, and alter manually the said means of adjustment of the axial position of the distributor plungers. This regulation must be carried out at the beginning of each work cycle of the machine, and normally also within a single work cycle, owing to variables associated for example with pressure, temperature and humidity of the working environment or the product used, or other parameters of use, which can modify the weight of the doses of product formed in succession by the distributors, even if their distribution chamber remains volumetrically unaltered. In order to limit these variables, the greatest possible control is maintained over all the operating parameters of the machine which could generate these variables, and the machine is sometimes also installed in a controlled atmosphere chamber, this condition often also being necessary because of requirements of sterility in processing the medicinal product to be packaged, and/or in order to avoid dispersion of the latter in the external environment where the operators are located. In order to limit the negative consequences which can arise in production, as a result of these variables, use is also known of means which check statistically the weight of the capsules with the doses of products formed by the distributors, and which indicate whether the weight detected is within the predetermined limit values, or whether it is above or below these limits, also specifying the size of the error. On the basis of this information, the operator can alter the adjustment means for regulation of the volume of the distributors, and in serious cases, can stop the machine.
The problems raised by the known art can be summarised as follows:
The presence of highly qualified employees is required in order to set the distributor carrousel correctly at the start of each work cycle, control the operation of the carrousel and to carry out any necessary adjustments of volume of the distributors; PA1 If adjustment is necessary, the entire machine must be stopped, and if there is a controlled atmosphere chamber, adjustment must be carried out from the exterior, through a porthole and wearing rubber gloves, and thus in a manner which is not at all convenient; PA1 Cyclical stoppages of the machine in order to carry out the said adjustments of volume of the distributors can affect the balance of operation of the machine, cancelling out or delaying the effects which should be derived from the adjustments.